The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Separation of oil and water, and especially separation of water from heavy crudes is often challenging due to the relatively large volume, small differences in oil and water densities, and viscosity of the feed. Some facilities add a light hydrocarbon diluent to facilitate separation oil and water; however, the use of diluent often adds significant cost and increases volumes and equipment size. In another known approach to remove water from the crude, a flash treating process can be implemented in which the crude is heated to a temperature that allows flashing of steam from the crude to so produce dewatered crude and a steam stream as described, for example, in U.S. Pat. No. 6,372,123. Unfortunately, such flashing typically generates substantial quantities of foam that must be sprayed down with a portion of the dewatered crude. Thus, such approach requires one or more recycle pumps to move significant amounts of dewatered liquid for foam suppression and will so add to equipment and operational costs. For example, a typical installation will require 2-3 times the throughput to suppress foam, which forces the separation vessel to be significantly large.
All publications identified herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Flashing is also known in preflash drums that flash off light boiling hydrocarbons from a liquid feed to a crude unit. Preflash drums are a known source of foam problems where the light hydrocarbon vapors and the crude liquid tend to readily form bubbles. As a solution, vortex tube clusters can be implemented in the drum to reduce foam formation as is reported in PTQ Autumn 2004 article entitled “Foam Control in Crude Units”. While such solution is generally suitable for defoaming a liquid crude feed, it is limited to separating the light boiling hydrocarbons from the liquid feed that are both fed to the crude unit.
Therefore, even though various systems and methods for water removal from crude oil are known in the art, various disadvantages nevertheless remain. Thus, there is still a need to provide improved systems and methods for dewatering crude oil.